a. Field of the Invention
This invention relates to introducer sheaths, catheters and other devices configured to be maneuvered through a body. In particular, the invention relates to an improved handle assembly for use in navigating a deformable shaft of such a device within a body.
b. Background Art
A wide variety of medical devices are inserted into the body to diagnose and treat various medical conditions. Catheters, for example, are used to perform a variety of tasks within human bodies and other bodies including the delivery of medicine and fluids, the removal of bodily fluids and the transport of surgical tools and instruments. In the diagnosis and treatment of atrial fibrillation, for example, catheters may be used to deliver electrodes to the heart for electrophysiological mapping of the surface of the heart and to deliver ablative energy to the surface among other tasks. Catheters are typically routed to a region of interest through the body's vascular system. In a conventional approach, an introducer is used to puncture the skin surface and a sheath having an inner diameter greater than the outer diameter of the catheter is threaded through the vasculature to a region of interest. The catheter is then moved longitudinally through the sheath to the region of interest either manually by a clinician or through the use of electromechanical drive systems.
Maneuvering a catheter or sheath through the body requires precise control for effective diagnosis and treatment and patient safety. Conventional catheters and sheaths include a deformable shaft or body and one more steering wires that extend from a proximal end of the shaft to a distal end of the shaft. A handle is coupled to the proximal end of the shaft and includes means for pulling and/or pushing the steering wires to place them under compression or tension in order to control translation and deflection of the distal tip of the shaft. In one conventional handle, a pair of steering wires are coupled to diametrically opposite points on a rotatable body controlled by the physician. Rotation of the body causes movement of the steering wires. To allow for a sufficient range of movement of the steering wires, the wires must be coupled to the rotating body at a relatively large distance from the center of the rotating body. As a result, the wires must be bent at relatively sharp angles proximal and distal to the rotating body as they assume a substantially more linear orientation relative to the body of the catheter or sheath. Bending of the wires leads to an increase in friction between the wires and surfaces engaged by the wires within the catheter or sheath and increases the chance that a steering wire will break.
The inventor herein has recognized a need for a handle assembly for use in navigating a deformable shaft of a medical device within a body that will minimize and/or eliminate one or more of the above-identified deficiencies.